While I myself am bullish on AAPL, I would suspect that the following are a few reasons investors are skeptical.
1) Essentially every product Apple offers has been recently overhauled, and any new product Apple releases is likely to have lower margins.
2) The most popular Apple products selling right now are the ones with lower margins, which is great for user market, but not for the stock market.
3) The one product that could really turn things around, the Apple television, is only rumored, and could be released any time been now and 2 years from now. The fact that Apple must negotiate with content networks is not reassuring.
4) Apple's stock price ebbs and flows with the rumor mill. From what I can tell, it's much weaker than usual.